Axial flow jet motor with reversely rotating continuous combustion type combustion products generator and turbine



March 10, 1953 L w, SE m- AXIAL FLOW JET OTOR WITH REVERSELY ROTATING CONTINUOUS COMBUSTION TYPE COMBUSTION PRODUCTS GENERATOR AND TURBINE Filed Jan. 20, 1947 2 SHEETS-SHEET 1 IN V EN TOR.

Donald- I lflfieziferzi,

BY 6 ,1 W

March 1953 D. w. SEIFERT v AXIAL FLOW JET MOTOR WITH REVERSELY ROTATING CONTINUOUS COMBUSTION TYPE COMBUSTION PRODUCTS GENERATOR AND TURBINE 2SHEETS--SHEET 2 INVENTOR. flo maid Zflfisferi,

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Filed Jan. 20, 1947 Patented Mar. 10, 1953 AXIAL FLOW JET MOTOR WITH REVERSELY ROTATING CONTINUOUS COMBUSTION TYPE COMBUSTION PRODUCTS ATOR ANDTURBINE Donald W. Seifert, Winona, Minn.

Application January 20, 1947, Serial No. 722,988

(o1. (so-39.35)

- 22 Claims. 1

This invention relates to jet motors.

In a co-pending application filed by me January 20,1947, Serial No. 722,987, I have disclosed and described a form of jet motor and its principle of operation.

The present disclosure includes certain developments not included in the above-mentioned application. For purposes of convenience, the following is a statement of the general nature of a jet motor and may refer to subject matter common to both the previously mentioned invention, and the present, after which a statement of the improvements of the present invention follows.

The jet motor of the present invention is of the type which is propelled by expulsion of gases rearwardly out of the motor, and which picks up air for combustion when traveling. This is distinguished from rockets in which the air for combustion is contained in the fuel provided in the device.

By way of general explanation the present invention applies to that type of fuel burning device in which the device is propelled forward by rearward expulsion of gases of combustion; the gases of combustion in the same propelling process rotate a driving element which in turn operates a compressor. The compressor then picks up air in the travel of the device, compresses it, and delivers it to the driving element where it supports combustion of the fuel.

An important advantage resides in this feature; in previous jet propelled devices, the combustion chamber was stationary, and the gases of combustion were then driven through a turbine which operated a compressor. In the device of the present invention, a plurality of combustion chambers are arranged in a rotating driving means, where the combustion takes place, so that the actual process of combustion produces a direct and immediate rotating force :on the driving means.

The combustion driving means above referred to may also be referred to as an athodyd or athodyd stage. Athodyd is a word recently coined from aero-thermo-dynamicduct, and ap plies particularly to jet motors. This driving element may be referred to herein both as an athodyd driving means and a combustion driving means.

A portion of the power generated by the expulsion of gases out of the motor is utilized in driving the compressor, but the air compressed by the compressor accomplishes more rapid combustion, resulting in higher speedsof the device.

Accordingly, the efficiency of such a device is increased as the speed of the motor is increased.

starting of the device.

GEN ER- This is a peculiarity of jet motors, and because of that condition, when the efliciency drops to a certain point, operation of the device ceases. As a correlative of this phenomenon, the device must be given an impulse by some auxiliary force to attain initial speed for the jet propulsion feature to become effective.

The present invention utilizes an elongated cylindrical casing; a shaft is rotatably mounted centrally of the casing, and the compressor and athodyd stage mentioned above are rotatably mounted on the shaft. The casing is open at both ends taking in air at one end and expelling it at the other end.

Fuel is supplied to the athodyd driving means and an ignition device is provided for initial After the motor operates for a short time, the athodyd driving means becomes heated and the heat therefrom ignites the fuel; thereafter the ignition system is no longer required.

Another phenomenon peculiar to jet motors is that while both ends are open, the expulsion of gases is effected in only one direction, such expulsion being in the same direction as the influx of air which is brought in by the travel of the machine. The incoming air is compressed inside the motor and drives the gases of combustion out the opposite end.

An advantage of the present invention, as distinguished from my previously mentioned invention, is that it includes a compressor having inner and outer rotary elements, and an athodyd driving means having inner and outer rotating driving elements. The rotary elements of the compressor are driven by respective elements of the athodyd driving means.

The provision of counter rotating elements of a compressor delivers higher pressure of air, and the provision of separate elements in the combustion driving means distributes the: power for greater efiiciency.

Another advantage of the present invention is that gearing of different ratios may be interposed between the respective elements of the athodyd driving means and the compressor to obtain different relative speeds between the parts.

With these and other objects in view, :my invention consists in the construction, arrangement and combination of the various parts of my device whereby the objects contemplated are attained, as hereinafter more fully set-forth, pointed outin the claims and illustrated in th accompanying drawings, in which: 1

Figure 1 is a longitudinal sectional view of one form of my invention;

Figure 2 is a longitudinal sectional view of another form of the present invention;

Figure 3 is a view taken approximately on line 3-3 of Figure 1;

Figure 4 is a view taken approximately on line 4-4 of Figure 1;

Figure 5 is a view taken substantially on line 5-5 of Figure 1;

Figure 6 is a view taken substantially on line 6-6 of Figure 1;

Figure '7 is a diagrammatic developed view of the blades and buckets of the turbocompressor, taken substantially on line 'I'I of Figure l; and

Figure 8 is a longitudinal sectional view of a compressor and air sealing means therefor.

Figure 9 is a fragmentary View of. a modified form of the inner and outer rotor combination illustrated in Figure 1.

Figure 10 is a View taken substantially on line IflIll of Figure 9.

The device of Figure 1 Referring in detail to the drawings, the jet motor of Figure 1 includes a cylindrical elongated casing I2-having an outwardly flaring open inlet end I4, and an outlet end I6 tapered rearwardly along air-flow lines and terminating in a substantially cylindrical outlet opening it. If desired, the casing I2 can be tapered along air fiow lines to produce more efficient air flow, and the working parts designed to conform to the shape of the casing. A shaft is rotatably mounted axially in the casing in bearing supports 22 and 24. The bearing support 22 has a central opening for the shaft 20 and a sleeve supporting shaft 20 which will be referred to later, and includes a central portion 25 and radial fins 28 extending outwardly from the central portion 25 and secured to the casing I2. The bearing support 24 includes a central portion 30 and radial fins 32 extending outwardly from the central portion 30 and secured to the casing I2.

A turbocompressor indicated generally at 34 is rotatably mounted on the shaft 20. The compressor. 34 includes a central rotary element 36 which may be fixedly secured to the shaft 20, and includes a plurality of sets of blades 38 extending radially outwardly therefrom. The compressor 34 also includes an outer rotary element 40 in the form of a hollow drum 4! surounding the inner rotary element 36. Extending inwardly from the inner peripheral surface of the drum 4| are a plurality of sets of buckets 42 disposed alternately between adjacent sets of blades 38. The blades 38 and buckets 42 are curved oppositely from each other, as shown in Figure '7, for more efficient compression action. The outer rotary element 48 includes end plates 44 secured to sleeves 46 and 48 which are freely rotatable on the shaft 20. The plates 44 have outwardly extending radial fins 50 which are connected to the drum portion 4| of the outer rotary element 40. The sleeve 46 is fitted in the central opening of the bearing support 22 and the sleeve 48 is positioned in the central opening of the bearing support 24. The plates 44 may be secured to the drum 4| and respective sleeves in any well known manner.

The athodyd driving element is indicated generally at 52, and includes a central or inner driving element 54 fixedly secured to and rotatable with the shaft 20. The inner driving elerior of the device.

ing an annular space 58 formed therein adjacent its outer periphery. Secured to the outer surface of the drum 56 are a plurality of blades 50 extending radially outwardly therefrom. Formed in each blade 50 is a passage 62 which communicates with the annular space 58 and terminates in jets 64 opening out of the blade tangentially therefrom. The shape and positioning of the blades 60 will be referred to later.

An outer driving element is indicated generally at 6B and includes a hollow ring-like member 68 disposed outwardly beyond the inner driving element 54, and having an annular space Iii. Positioned on the inner surface on the ring-like member 68 is a plurality of blades I2 of a shape symmetrical with the blades 60, but being dif ferently disposed, and extending down to and in proximity with the outer tips of the blades 56. Leading from the spaces I0 through the blades I2 are passages terminating in jets I6 opening out of the respective blades tangentially thereof and into the spaces therebetween.

The ring-like member 68 is secured to a spiderlike member indicated generally at I8 (see Figure 4). The member '58 includes a plurality of arms or fins 88 having outer segments 82 and inner segments 84. A ring 86 is formed on or connected with the joints between the segments of the fins 823. The inner segments 3 are connected to a hub 88 which is formed on or connected to sleeve 48 for rotation therewith in any convenient manner.

Fuel is supplied to the combustion driving means through an inlet passage 90 on the exte- The passage 98 leads down through one of the fins 32 and the central portion of the bearing support 24 as indicated at Q2. Passage 92 then communicates with the pas sage 9% in the sleeve 48, which communicates with passage t6 formed in the shaft 25. The passage 94 in the sleeve 48 is provided at its opposite ends with annular recesses to communicate with passages 95 and 52 in all positions of rotation of the various elements. The passage 96 in the shaft 2t then communicates with a passage 88 which leads outwardly through the central part of the driving element 54 and finally communicates with the annular space 58 in the driving element 54. It will be recalled that from the annular space 58, passages 62 and jets 54 lead from the tubes iii to and open into the spaces between the blades '55.

Another passage I00 is formed in the sleeve 48 and leads from the passage 94 axially of the sleeve 48 and then outwardly through the hub 68 and fins iii in the outer driving element St and finally communicates With the annular space it in that driving element.

Auxiliary outlet openings I 02 lead from the passage 532 in the bearing support 24 and open toward the athodyd driving means 52. One such outlet opening I02 is associated with each driving element 54 and 66. Solenoid closure means H14 are provided for opening and closing the outlets IBZ. A Venturi-shaped ignition glow plug Hi5 is disposed at the outlet of each opening H12, through which fuel passes on emerging from the openings I02. An ignition circuit 958 is provided for operating the ignition means I06 and the solenoid operated closure I04.

A shield i I ll surrounds the sleeve 45 at the lead" ing end of the device for forming an annular inlet area III conformingto the annular space occupied by the blades 38 and buckets 42 and'defiecting air therethrough, Similarly, another shield H2 is formed at the rear and secured to the shaft 20. The shield H2 covers the central portion of the inner driving element 54 forming an annular outlet area I i3, and tapers rearwardly to a point, conforming generally with the contour of the trailing end I6 of the device.

Operation of the device of Figure 1 As mentioned hereinabove a jet motor must be started by some auxiliary force for the mechanism to become effective. This may be done by connecting an auxiliary motor to the contra r tating shafts 2!) and 4G for initiating rotation thereof.

After the initial starting force is applied and the motor driven to a predetermined speed, the compressor 34 is driven by the driving means 52. Referring to Figure 5, the blades 12 are pecu liarly shaped, forming the athodyd spaces 13 between adjacent blades. Each space 13 has an enlarged intermediate portion 6 M and a restricted dimension H at the right end, or inlet, and another restricted dimension l 15 at the left end, or outlet. Outwardly beyond the restricted di mensions H5 and H6 are outwardly diverging spaces H1 and H8. When fuel is injected into the spaces H4 and ignited therein, the gases of combustion are expelled rearwardly out through the restrictions H6. Such rearward expulsion occurs when pressure is builtup in the forepart of the spaces H4, and this expulsion out of the rear of the device drives the device forward, and at the same time, the expulsion of combustion gases out of the spaces 13 imparts a rotary motion to the blades 12, and thus also rotates the driving element 55.

Comparison of Figures 5 and 6 will show how opposite rotation of the driving elements 54 and it is accomplished. Figure 5 shows the angular relation of the blades 12 whereby, when gases of combustion are expelled rearwardly of out the spaces 13, rotation of the driving element 66 is toward the reader as observed in Figure 5. In Figure 5 it will be noted that the angular disposition of the blades 66 is in the opposite direction from the blades 12, with respect to the direction circumferentially of the device. Expulsion of gases of combustion out of the restrictions H5 in the spaces '13 in Figure 6 will rotate the driving e1ement 54 in a direction away from the observer as viewed in Figure 6.

Driving element 66 is connected with outer rotary element 40 of the compressor through sleeve 48; and drivin element 5a is connected with inner rotary element of the compressor .arough shaft 20. It will therefore be seen that opposite rotation of the drivingelements produces opposite rotation of the rotary elements of the compressor.

When the device is initially started as by means of an auxiliary motor, the compressor 84 builds up air pressure and delivers it rearwardly toward the driving means 52. Fuel is injected in the passage 99 which finds its Way to the jets as and "it. and into the spaces M between the respective blades 6!! and 12. Also in the starting operation, the solenoid operated closure its is opened, permitting fuel to emerge out of the outlets Hi2, and the ignition means 106 are operated for igniting fuel emerging from the outlets Hi2. This ignites the fuel emerging'from the jets 64 and 16 as well, since the outlets H12 are in close proximity to the spaces H5 and HT. l h

After a predetermined speed is attained and a predetermined length of time expires, the

bladesfifl and lfbecome' 'heated and: the heat from' these blades is sufiicient to ignite the fuel. At this point the ignition means 1% may be cut out. Upon sufiicient pressure being built up by the compressor 34, the gases of combustion in the driving means 52 are forced rearwardly out of the device. This rearward expulsion forces the motor forward, increasing the action of the com pressor, and increasing the efficiency of the driving element in such a manner that each'feature adds to the action of the other, resulting in increasing speed and efficiency.

l The tangential disposition of the jets E4 and 16 produces an added turning force on the respective driving elements 54 and B6 of the athodyd driving means, The reaction against the blades Eli and 12 from the pumped fuel emerging from the jets adds to theforce of combustion in rotating the driving means, similar to the action of a lawn sprinkler.

The action of the compressor 34 in compressing air and delivering it to the fear is well known to those familiar with tubines and turbocom pressors. Figure 7 shows the curvature and. relative angles of the blades 38 and the buckets 42. This relative angularity delivers compressed air toward the rear, or left, and through the athodyd driving means 52. It will be understood that since the separate elements of the driving means 52 rotate in opposite directions, that streams of air must be directed in opposite directions circumferentially of the device into the respective driving elements 54 and 66, for greater efficiency. The fins 32 of the bearing support as are given opposite directions of inclination midway between their outer and inner extremities. The outer extremities of the fins 32 are shown at I20 in Figure 5, are streamlined in-cross-section and are directed in nearly the same angular relation as the blades 12. The portions I253 of the fins 32 therefore form a stream of air and deflect it directlytoward the diverging spaces Ill and into the spaces H4." The blades '52 rotates in a direction against such stream of air and the shape of the diverging spaces III is such as to readily scoop up the air fromthat stream.

Due to the opposite rotation of the inner driving element 54, the inner portions I22 of the fins 32 are angled in the opposite direction. (compare Figures 5 and 6), The'portions I22 thereby form a stream of air and deflect it circumrferentially of the device in a direction opposite to that deflected by portion I28, and since the blades 60 are rotating in the opposite direction from the blades 12 they scoop up the air from the latter stream readily.

To accommodatethese separate streams of air the fins Bl] in the outer driving element 86 have a peculiar formation. The outer segments 82 of the fins are streamlined incross-section as indicated in Figure 5. These fins B2 rotate with the blades 12 (since they are connected therewith) and do not add ,to or detract from the passage of air therebetween, i

However, the inner segments 84 of the fins 39,

which are adjacent the blades 6i) of the inner driving element 54, rotate in the direction opposite the blades Gil. It is therefore necessary to form the segments 8.4 differently from the segments 82. These segments 84 cannot be given a streamlined shape, and be disposed at the same angle as the blades filLbecause at this angle the direction of rotation of the segments 84 might tend to have a backing-up effect on the airstream, unless they weretraveling at onepartic- 'ular-speed. Therefore, to accommodate different speeds, these segments 84 are formed round in cross-section tohave as little effect as possible on the flow of air therepast.

If desired, a tube or cylinder 200 may be secured to the inner ends of the blades I2 and a tube or cylinder'2fl2 may be secured to the outer ends of the blades 60, to prevent air from being churned between the two sets of blades.

It will be noted that in the device of Figure l the inner rotary element 36 of the compressor and the inner driving element 54 of the driving means are directly connected with the shaft and therefore rotate in unison. Also, the outer rotary element 40 of the compressor and the outer driving element 66 of the driving means are directly connected through the sleeve 48 and therefore rotate in the same direction with each other, and opposite to their counterparts. It may be desirable to impart various speeds to the various elements, and to accomplish this result reference may be had to the form of the device of Figure 2.

In the initial starting of the device, efficiency will be improved by imparting an impulse to both the shaft 20 and the sleeve 49 thereon, in opposite directions, to rotate both rotary elements of the compressor 34, and consequently both driving elements of the combustion driving means 52.

The shaft 20 may be utilized as an auxiliary output shaft for operating auxiliary power plants, such as the lighting system on a ship on which the device can be used. Similarly, the sleeve 46 may be used as an auxiliary output shaft.

he device of Figure 2 Figure 2 includes gearing means for providing driving connection between the driving means 52 and the compressor. 34. Such gearing and its adaptations will be described in detail in Figure 2, and those features of Figure 2 which are similar to Figure 1 will not be dwelt upon in detail.

The turbocompressor 34 of Figure 2 includes an inner rotary element 36 which instead of be-- ing directly connected with the shaft 20 is secured on a sleeve I24. The sleeve I24 is freely rotatable on the shaft 20 and extends rearwardly where a ring gear I26 is secured thereto. Meshing with the ring gear I26 are a plurality of planetary gears I28 supported in the bearing support 24; and meshing with the planetary gears I28 is a sun gear I30 fixedly secured to the shaft 20.

Fixed to the outer rotary element ii) of the compressor, and extending rearwardly therefrom, is a tubular extension I32 in the outer end of which is formed a ring gear I34. Meshing with the ring gear I34 are a plurality of planetary gears I36 mounted on the bearing support 24. A sun gear I38 is'arranged to mesh with the plan etary gears I36 and is fixed on the forward end of sleeve I40. The sleeve I40 corresponds with the sleeve 48 in Figure 1 and is connected with the outer driving element 66 of the driving means 52, in any suitable manner.

It will be noted that the inner driving element 54 of the driving means 52 has driving connection with the inner rotaryelement of the compressor, and likewise, the outer driving element 66 of the driving .means 52 has driving connection with the outer rotary element 4!! of the compressor. The relative rotation of the counterparts of the compressor and of the driving means are the same as in Figure 1, although the driving connections are through gearing instead of be ing direct as in Figure 1. The gearing may be 8 varied, as to speed ratios, for increasing or decreasing the relativerotation of the parts of the compressor.

Although the rotation between the counterparts of the compressor and of the driving means is the same in connection with Figs. 1 and 2, the interconnected elements between the compressor and driving means rotate oppositely, i. e., the outer driving element 66 of the driving means rotates oppositely from the outer rotary element id of the compressor, and the inner driving element 54 of the driving means rotates oppositely from the inner rotary element 35 of the compressor. Accordingly, in the device of Figure 2, the blades 38 and buckets 42 will be reversed in direction of their pitch, as will the fins 28.

Reference may be had to Figure 6 for a means for preventing the passage of air through the device around the outside of the compressor. The casing I2 is provided with an enlarged portion I 42 for accommodating the compressor 34. The outwardly flaring inlet portion I4 is of about the same diameter as the inner diameter of the drum i! of the outer rotary element 49 of the compressor. It is naturally desirable to have all of the air passing through the device to pass through the compressor, and to that end an angle member I44 is secured to the inner surface of the casing I2 in the enlarged portion I42, and in engagement with the outer rotary element 48 of the compressor. This prevents air from passing through the spaces I45 outwardly of the outer rotary element 453- of the compressor, and deflects all of the air through the compressor.

The efiiciency of the device is improved due to the fact that combustion takes place directly in the rotary driving means. This is distinguished from previous types of jet motors where gases passed from a stationary combustion space to a turbine driving element with consequent loss of efliciency. In the present device such loss of efficiency is eliminated.

Although I have herein shown and described certain preferred embodiments of my invention, manifestly they are susceptible of modification and rearrangement of the parts without departing from the spirit and scope thereof. I do not, therefore, wish to be understood as limiting my invention to the precise forms herein disclosed, except as I may be so limited by the appended claims.

I claim as my invention:

1. In a jet motor, a casing having open ends adapted for flow of air therethrough, a shaft rotatable in said casing, an inner rotor mounted on said shaft, an outer rotor mounted on said shaft and having a portion overlapping said inner rotor; a first set of blades extending generally radially from said inner rotor toward said overlapping outer rotor portion, a second set of blades extending generally radially from said overlapping outer rotor portion toward said inner rotor, each of said two sets of blades being formed with fuel passages therein terminating tangentially of said blades for injecting fuel in the spaces between adjacent blades, each of said two sets of blades extending radially short of the ends of the opposed set of blades and with their leading edges offset from their trailing edges in a direction opposed to the direction of offsetting in the opposed set whereby said rotors are caused to rotate in opposite directions, and means for supplying fuel through said passages.

2. A jet motor according to claim 1 having rotor blades whose sides are concave over a portion of 9.. their axial length from their leading edges to their trailing edges;

3. A jet motor according to claim 1 comprising stationary vanes extending radially therein ahead of said rotors and having their trailing edges offset from their leading edges in the same directions as the blades of said rotors downstream thereof.

i. A jet motor according to claim 1 comprising an outer rotor having a hub mounted on said shaft and radial projections connecting said hub with the outer rotor portion overlapping said inner rotor, said radial projections being formed ahead of said outer rotor blades as vanes having their leading edges offset from their trailing edges in. the same direction as the outer rotor blades.

A' jet motor according to claim 4 in which said radial projections have a substantially round cross sectional form between said hub and said vanes.

6. A jet motor according to claim 1 comprising a bearing for saidshaft and radial bearing support projections from said bearing connecting the bearing to said casing and formed with fuel passages therein, said outer rotor having a central hub rotatable on said shaft and radial rotor supporting projections from said hub connected to the overlapping outer rotor portion, said hub and the radial rotor supporting projections being formed with fuel passages therein cornmunicating with the fuel passages in said outer rotor blades and with the fuel passages in said bearing support projections and said shaft being formed with fuel passages therein communicating with the fuel passages in said inner rotor and withthe fuel passages in said bearing support projections.

'7. In a jet motor, a casing having open ends adapted for flow of air therethrough, a shaft rotatable in said casing, an inner rotor mounted on said shaft, an outer rotor mounted on said shaft and having a portion overlapping said inner rotor, a first set of blades extending generally radially from said inner rotor toward said overlapping outer rotor portion, a second set of blades extending generally radially from said overlapping outer rotor portion toward said inner rotor, the leading edges of each set of rotor blades facing axially in the same direction and being spaced axially forward of their trailing edges, each of said two sets of blades extending radially short of the ends of the opposed sets of blades and with their leading edges of each set of blades offset from their trailing edges in a direction opposed to the direction of offsetting in the opposed set of blades.

8. A jet motor according to claim '7 having rotor blades whose faces are concave over a portion of their axial length.

9. A jet motor according to claim 7 having rotor blades formed with fuel passages therein terminating on the trailing faces of said blades and pointing in a direction opposite to the direction of rotation of said blades, said motor further comprising means for supplying fuel to said passages.

10. A jet motor according to claim 9 wherein the rotor blade fuel passage terminating on said trailing face point in a direction having a component tangential to said trailing face.

11. A jet motor according to claim 9 having rotor blades Whose faces are concave over a portion of their axial length and having the rotor blade fuel passages opening at said concave portion of the blade face.

12. A jet motor according to claim 7 including at least one tubular element extending axially of said motor between the opposed sets of rotor blades.

13. A jet motor as set forth in claim 7 including at least one tubular element extending axially on said motor between the opposed set of rotor blades and said tubular element being secured to the tips of the blades of one of said rotors.

14. A jet motor according to claim '7 having rotor blades formed with fuel passages therein terminating on the trailing faces of said blades and pointing in a direction opposite to the direction of rotation of the rotor.

15. In a jet motor, a casing having open ends adapted for flow of air therethrough, a shaft in said casing, an inner axial flow rotor mounted on said shaft, an outer axial flow rotor mounted on said shaft and having a portion overlapping said inner rotor, a first set of blades extending generally radially from said inner rotor toward said overlapping outer rotor portion, a second set of blades extending generally radially from said overlapping outer rotor portion toward said inner rotor, each of said two sets of blades extending radially short of the ends of the opposite set of blades, the axial component of air flow through each set of blades being in the same direction, and means including the shape of the blades of the rotors for causing, said rotors to rotate in opposite directions.

16. A device as set forth in claim 15, wherein a portion of the faces of each blade are concave, whereby each pair of adjacent blades form an enlarged combustionchamber therebetween.

17. A jet motor as set forth in claim 15 comprising a set of radial projections between the shaft and the casing spaced upstream of the rotors, fuel passages in said inner and outer rotors and fuel passages in said radial projections com municating with the fuel passages in said inner and outer rotors.

18. In a jet motor, a casing having open ends adapted for flow of air therethrough, a shaft in said casing, an inner axial flow rotor mounted on said shaft, an outer axial flow rotor mounted on said shaft and having a portion overlapping said inner rotor, a first set of blades extending generally radially from said inner rotor towards said overlapping outer rotor portion, a second set of blades extending generally radially from said overlapping outer rotor portion towards said inner rotor, each of said two sets of blades extending radially short of the ends of the opposed set of blades, each blade of said inn-er and outer rotors having a leading face and a trailing face, and the leading face of each blade and the opposite facing trailing face of the previous blade being shaped to form therebetween a flow passageway having an enlarged combustion chamber formed intermediate the ends thereof.

19. A jet motor as set forth in claim 18 including fuel passages extending radially through said blades and terminating in jets positioned adjacent the outer tips of the blades and opening to said combustion chambers.

20. A jet motor as set forth in claim 18 including a throat in said flow passageway downstream of said combustion chamber, and an expansion nozzle downstream of said throat.

21. In a jet motor, a casing having open ends adapted for flow of air therethrough, a shaft in said casing, an inner axial flow rotor mounted on said shaft, an outer axial flow rotor mounted 11' on said shaft and "having a portion overlapping said inner rotor, a first set of blades extending generally radially from said inner rotor towards said overlapping outer rotor portion, a second set of blades extending generally radially from said overlapping outer rotor portion towards said inner rotor, each of said two sets of blades extending radially short of the ends of the opposed set of blades, each blade of said inner and outer rotors having a leading face and a trailing face, the leading face of each blade and the opposite facing trailing face of'the previous blade being shaped to form therebetween an axial flow passageway comprising, in order passing downstream, a first throat, a combustion chamber of enlarged Width, a second throat, and an expansion nozzle.

22. In a jet motor, a casing havingopen ends adapted for flow of air therethroug-h, a shaft in said casing, an inner axial flow rotor mounted on said shaft, an outer axial flow rotor mounted on said shaft and having a portion overlapping said inner rotor, a first set of blades extending generally radially from said inner rotor towards said overlapping outer rotor portion, a second set of blades extending generally radially from said overlapping outer rotor portion towards said inner rotor, each of said two sets of blades extending radially short of the ends of the opposed set of blades, each blade of said inner and outer rotors having a leading face and a trailing face, the leading face of each blade and the opposite facing trailing face of the previous blade being shaped'to form therebetween a flow passageway having an enlarged combustion chamberformed intermediate the ends thereof, the axes of said 12 combustion chambers being straight and disposed at an angle to the axis of the motor, a throat in each said flow passageway downstream of the combustion chamber and an expansion nozzle downstream of said throat, and the portion of the blade leading face downstream of said throat extending axially of the combustion chamber axis further than the portion of the blade trailing face downstream of said throat, whereby the flow issuing from the flow passageway is turning towar-da direction parallel to said motor axis.

DONALD W. SEIFERT.

REFERENCES CITED The following references are of record in the file of this patent;

UNITED STATES PATENTS Number Name Date 1,388,707 Heinze Aug. 23, 1921 1,868,143 Heinze July 19, 1932 1,980,435 Heinze Jan. 1, 1935 2,201,099 Roe May- 14, 1940 2,243,467 J endrassik- May 27', 1941 2,360,130 Heppner Oct. 10, 1944 2,404,767 Heppner July 23, 1946 2,410,538 Walton Nov. 5, 1946 2,425,904 Vernon Aug. 19, 1947 2,428,330 Heppner Sept. 30, 1947 2,479,777 Price Aug. 23, 1949 FOREIGN PATENTS Number Country Date 23,123 Great Britain Oct. 18, 1906 467,630 Great Britain June 21, 1937 

